1. Field of the Invention
The method relates to convective heat transfer in wire lashings of steel and non-ferrous metal and has the goal to realize the heat and flow conditions for rapid and uniform heating and cooling in a continuous-heating furnace of wire rings which are stacked to form a lashing. This task is solved according to the invention essentially in that the stacks of wire lashings are placed in cycle with the furnace charge of a roller bottom furnace always between two upper and lower pressure openings in a strong circulation of furnace gas of the respective blow-in stations and thus the furnace gases with their high proportion of kinetic energy of flow impinge upon one another in the central hollow space of the stack and consequently the flow is retained while the static pressure is increased and flows out from there uniformly and turbulently through the windings of the lashings, due to the conversion of potential energy to kinetic energy.
2. Description of the Prior Art
In many respects it is an important goal to subject wire rings uniformly to thermal treatment. Not only is heating energy to be saved, but it is also to be accomplished that a primary material is made available for further processing which is uniform in its metallurgical and mechanical properties. The present state of the art has not yet made it possible that all parts of a wire ring are subjected during thermal treatment to the greatest extent to the same conditions of heat transfer. Particularly the fact plays an important part that the process of heating and cooling which is very time-dependent is exactly that stage within the scope of thermal treatment during which making the heat transfer uniform is the decisive measure. Taking the wire ring geometry into consideration, it is clear that the participation of heat conduction and radiation of heat in heating a wire ring is strongly reduced as compared to the convection effect. This makes it clear that an improvement of the thermal treatment of wire rings can only be achieved by means of that method according to which the convection of the furnace gases in the heating zone of a roller bottom furnace is made uniform and is simultaneously increased for all parts of a stack of wire lashings.